[encoderer]

Complex scripts?

I hit the "reply" button to tell you that no, no amount of "complex scripting" is as mentally challenging as developing a Turing complete language.

But maybe you mean scripts as any program? In that case, I agree that developing things like, I don't know, database engines and file systems and such are equal in complexity to developing a language.

I suppose the only caveat is that those things are usually teams -- sometimes huge teams. A language is often a 1-man or small team effort.